Introduction to Modella

In the design of bipolar analogue integrated circuits, greater flexibility is often achieved when both NPN and PNP transistors are incorporated in the circuit design. Many present-day bipolar production processes use the conventional lateral PNP as the standard PNP transistor structures. For accurate modelling of such a lateral PNP transistor it is important to take the complex two-dimensional nature of the transistor into account. The physics based model Modella (MODEL LAteral) does exactly this, using a modelling approach whereby the main currents and charges are independently related to bias-dependent minority carrier concentrations. Current crowding effects, high injection effects, and a bias dependent output impedance are all taken into account.

Read more about Modella.

Model definition of Modella

The model definition of Modella is available as a pdf file: Level 500 .

The history of the model can be found here .

Source Code & Library

The source code of Modella is available here.
The file called "device_tpl500.c" contains the majority of the Modella code. If you use the included solver, please make sure that you compile on a system that supports Fortran 77.

The history of the source code can be found here.

The models are included in a dynamically loaded library called SiMKit.

SiMKit is related to the following circuit simulators used within NXP:

• Pstar, the circuit simulator from NXP
• Spectre, the circuit simulator from Cadence
• ADS, the circuit simulator from Agilent

You can read how to download and install the libraries here.

The source code is protected by Copyright © 1991, 2007, NXP.

Additional documentation

• "Physically Based Compact Modelling of Lateral PNP Transistors", F.G. O'Hara, Philips Research, Nat.Lab. Unclassified Report 2001/804, 2001 (of 5.9MB).

Related Publications

Further information on Modella is available in the following related publications:

• "MODELLA - A New Physics-Based Compact Model for Lateral p-n-p Transistors", F.G. O'Hara, J.J.H. van den Biesen, H.C. de Graaff, W.J. Kloosterman and J.B. Foley, IEEE Trans. Electron Devices, vol. ED-39, no. 11, pp. 2553-2561, 1992 (of 790kB).
• "A new physical compact model for lateral PNP transistors", F.G. O'Hara, J.J.H. van den Biesen, H.C. de Graaff, and J.B. Foley, in Proceedings of the Bipolar Circuits and Technology Meeting, pp. 102-105, 1990 (of 258kB).

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